The four storey building had already been designed, but CEF decided to ‘lead by example’ and have it retrofitted as a model of energy efficient construction. There was more to this than altruism. CEF saved up to nine percent on the initial cost of the building, and expects a return on the investment in four years, thanks to savings on energy costs. Remarkably, CEF were not the only ones to benefit – the developers saved so much money they were able to construct a second, similar building alongside, and have become enthusiastic converts to sustainable construction. Here are examples of how energy efficient features were incorporated into the building:
Like most modern buildings, CEF House has plenty of large glass windows. These make use of double glazing – an outer and inner pane of glass with a gap between them – to reduce heat loss and gain. The inner pane is made of a substance known as Low-emissivity, or Low-E glass, which has a thin metallic coating that bounces back thermal radiation and prevents heat from creeping through the glass. The bottoms of outside doors are fitted with “door sweeps”that prevent draughts blowing in. To reduce heat flows from the parking basement to the ground floor, insulation panels made of compressed vermiculite were stapled to the basement ceiling. Vermiculite, a clay-like mineral, is found in abundance in South Africa, and is highly regarded for both its insulation and fireproofing qualities. Loose-fill vermiculite was packed into the cavity in the external brick walls to provide additional insulation. A 50mm insulation layer was also installed under the roof sheeting.
Lighting is one of the biggest consumers of electricity, particularly in offices where lights are often permanently switched on. CEF House installed a new system from Philips, never previously used outside Europe, called ActiLume. The lights look much like conventional fluorescent tube fittings, but their consumption, of 5-7 watts per square metre, is a fraction of the industry norm of around 30 watts. The most notable feature of ActiLume is its use of motion sensors which switch the lights off entirely when no-one is in the room, and light sensors that dim the tubes when enough daylight is coming in through the windows. Philips claims that in Europe these systems have reduced energy consumption by up to 75%. Another innovative technology is the lift, bought from a Finnish company called Kone, which has pioneered a mechanism that uses magnetic motors rather than hydraulics, resulting in a lighter lift cage that is said to use 80% less electricity. The Kone system is also able to confine all the mechanical parts to the hoistway at the top of the lift shaft, unlike conventional lifts which require a special, space-consuming machine room.
Two solar water heaters, each with 200 litre capacity, take care of all the hot water needs in bathrooms and kitchens. Sensors in basins and urinals cut out the chances of taps being left on, resulting in more efficient water use. Of course more is needed than simply a green building. People have to change their habits too. Video conferencing has been installed at CEF House and at subsidiaries like PetroSA in Cape Town, refineries in Mossel Bay, and at international offices, thus reducing the need for air travel. And as an experiment, 30 of the staff are having their private transport habits monitored, to encourage wider awareness of sustainable transport options like lift clubs and public transport.
More interventions are being planned, including the recycling of all waste, including glass, plastic, tin and used cooking oil, the addition of thin-film solar cell panels to the roof and a mini wind turbine to the front facade.